Which of the following is not an essential factor of a block?()
A: Previous block header hash
B: Time stamp
C: Index value
D: Cryptographic hash
A: Previous block header hash
B: Time stamp
C: Index value
D: Cryptographic hash
举一反三
- 比特币系统中，以下描述正确的是。 A: 某一个区块的块头(block header)中，存储着上一个区块的哈希指针（hash pointer） B: 某一个区块的块体（block body）中，存储着上一个区块的哈希指针（hash pointer） C: 某一个区块的块头(block header)中，存储着这个区块体（block body）中merkle tree的根哈希值 D: 一个区块链由N个区块和1个merkle tree构成的。
- Kingbase中创建Hash类型的索引正确的语法是( )。 A: CREATE INDEX xxx ON xxx WITH HASH (xxxx) B: CREATE INDEX xxx ON xxx USE HASH (xxxx) C: CREATE INDEX xxx ON xxx USING HASH (xxxx) D: CREATE INDEX xxx ON xxx FOR HASH (xxxx)
- Identify two situations in which the block header grows in a data block. （） A: when row directories need more row entries B: when there is row migration in the data block C: when there is an increase in the PCTFREE value for the data block D: when more transaction slots are required than are initially configured
- Identify two situations in which the block header grows in a data block. （） A: Awhen row directories need more row entries B: Bwhen there is row migration in the data block C: Cwhen there is an increase in the PCTFREE value for the data block D: Dwhen more transaction slots are required than are initially configured
- Before a block can be added to the chain, which job of the following is not necessary? ( ) A: A cryptographic puzzle must be solved thus creating the block. B: The computer that solves the puzzle shares the solution to all of the other computers on the network. C: The financial institution will verify this proof of work, if correct, the block will be added to the chain. D: The network will then verify this proof-of-work and, if correct, the block will be added to the chain.